‘Alí fell by an assassin's dagger, and Mu‘áwiya succeeded to the Caliphate, which remained in his family for ninety years. The Umayyads, with a single exception, were Arabs first and Moslems afterwards. Religion sat very lightly on them, but they produced some able and energetic princes, worthy leaders of an imperial race. By 732 A.D. the Moslem conquests had reached the utmost limit which they ever attained. The Caliph in Damascus had his lieutenants beyond the Oxus and the Pyrenees, on the shores of the Caspian and in the valley of the Nile. Meantime the strength of the dynasty was being sapped by political and religious dissensions nearer home. The Shí‘ites, who held that the Caliphate belonged by Divine right to ‘Alí and his descendants, rose in revolt again and again. They were joined by the Persian Moslems, who loathed the Arabs and the oppressive Umayyad government. The ‘Abbásids, a family closely related to the Prophet, put themselves at the head of the agitation. It ended in the complete overthrow of the reigning house, which was almost exterminated. _D._ The ‘Abbásid Dynasty (750-1258 A.D.). [Sidenote: The ‘Abbásid dynasty.] Hitherto the Arabs had played a dominant rôle in the Moslem community, and had treated the non-Arab Moslems with exasperating contempt. Now the tables were turned. We pass from the period of Arabian nationalism to one of Persian ascendancy and cosmopolitan culture. The flower of the ‘Abbásid troops were Persians from Khurásán; Baghdád, the wonderful ‘Abbásid capital, was built on Persian soil; and Persian nobles filled the highest offices of state at the ‘Abbásid court. The new dynasty, if not religious, was at least favourable to religion, and took care to live in the odour of sanctity. For a time Arabs and Persians forgot their differences and worked together as good Moslems ought. Piety was no longer its own reward. Learning enjoyed munificent patronage. This was the Golden Age of Islam, which culminated in the glorious reign of Hárún al-Rashíd (786-809 A.D.). On his death peace was broken once more, and the mighty empire began slowly to collapse. As province after province cut itself loose from the Caliphate, numerous independent dynasties sprang up, while the Caliphs became helpless puppets in the hands of Turkish mercenaries. Their authority was still formally recognised in most Muḥammadan countries, but since the middle of the ninth century they had little or no real power. _E._ From the Mongol invasion to the present day (1258 A.D.--). [Sidenote: The Post-Mongolian period.]